wasmtime: Add FreeBSD x86_64 check

We accidentally broke the build for FreeBSD when introducing the jit-icache-coherence
crate. To avoid this happening again, add a check job just to ensure that it can build.

See bytecodealliance#5323 and bytecodealliance#5331 for context.

.github/workflows/main.yml

@@ -140,6 +140,7 @@ jobs:
       with:
         submodules: true
     - uses: ./.github/actions/install-rust
+    - run: rustup target add x86_64-unknown-freebsd
 
     # Check some feature combinations of the `wasmtime` crate
     - run: cargo check -p wasmtime --no-default-features
@@ -172,6 +173,10 @@ jobs:
       env:
         CARGO_PROFILE_DEV_DEBUG_ASSERTIONS: false
 
+    # Check whether `wasmtime` cross-compiles to x86_64-unknown-freebsd
+    # TODO: We aren't building with default features since the `ittapi` crate fails to compile on freebsd.
+    - run: cargo check -p wasmtime --no-default-features --features cranelift,wat,async,cache --target x86_64-unknown-freebsd
+
   # Check whether `wasmtime` cross-compiles to aarch64-pc-windows-msvc
   # We don't build nor test it because it lacks trap handling.
   # Tracking issue: https://github.com/bytecodealliance/wasmtime/issues/4992